(1):
(prep.) In the space which separates; betwixt; as, New York is between Boston and Philadelphia.
(2):
(prep.) Used in expressing motion from one body or place to another; from one to another of two.
(3):
(prep.) Belonging in common to two; shared by both.
(4):
(prep.) Belonging to, or participated in by, two, and involving reciprocal action or affecting their mutual relation; as, opposition between science and religion.
(5):
(prep.) With relation to two, as involved in an act or attribute of which another is the agent or subject; as, to judge between or to choose between courses; to distinguish between you and me; to mediate between nations.
(6):
(prep.) In intermediate relation to, in respect to time, quantity, or degree; as, between nine and ten o'clock.
(7):
(n.) Intermediate time or space; interval.